FORMATION OF HYDROGEOLOGICAL CONDITIONS OF THE CHELYABINSK COAL BASIN AT THE POST-OPERATIONAL STAGE

Completion of the development of mineral deposits requires the development of new methods for managing areas disturbed by mining. The closure of mining facilities, especially those with a long history of mining forms a difficult environmental situation. This is determined by several factors. The development of deposits is accompanied by drainage measures changing the balance and structure of surface and groundwater flows, and new chemical agents are involved in the formation of the qualitative composition of the hydrosphere. The use of mined-out space during the development of schemes with roof collapse induces geomechanical processes forming the zones of collapse and displacement accompanied by disturbances of the Earth’s surface. The cessation of mine operation means the stop of drainage, which leads to the gradual filling of the depression funnel, the formation of flooding areas and mine water outlets to the surface. Unstable rocks in the quarry sides, on which there were landslides even during drainage, become especially dangerous areas when the water level rises. Taking in consideration that residential and industrial buildings are often historically located in close proximity to mines (sometimes even within the mining allotment), the hydrogeoecological problems of old industrial areas at the post-operational stage become very acute. At the same time, in many cases it is difficult to determine, which factors, natural (features of the geological structure, geomorphological conditions, water content of the period) or technogenic (cessation of drainage) are responsible for territory flooding, especially in the areas distant from the objects of completed mining. This gives rise to numerous speculations and leads to irrational technical solutions. By the example of the Chelyabinsk coal basin, the ecological and hydrogeological problems are considered that arise after mining completion and drainage termination. The measures for reducing their negative impact on the hydrogeoecological conditions of the territory are proposed.